Jeff Bauman was in the wrong place at the wrong time. He was standing at the finish line of the 2013 Boston Marathon, ready to cheer on his runner girlfriend, Erin Hurley, when the first bomb went off right by him. This resulted in both of his legs being amputated, a few inches above the knee. After a remarkable recovery, he now gets around, without even the aid of a cane, on a pair of state-of-the-art Genium prosthetic legs. He cowrote a book, “Stronger,” about his experience, and now splits his time doing public speaking and studying mechanical engineering at Middlesex Community College.

Jake Gyllenhaal had the kind of Hollywood contacts that got him a look at an early version of the ensuing script, expressed interest in playing the part of Jeff, then had to wait till a director — David Gordon Green — was chosen, and financing was put in place.

The former Costco worker and the star of “Donnie Darko” and “Nightcrawler” spent a lot of time together before filming began, helping Gyllenhaal figure out a way to capture the essence of Bauman in his portrayal of him. They again got together in Boston earlier this week to share their feelings about the film. There was some bromance in the air.

On finding out a film was going to be made from the book:Jeff: The book came out in 2014, and shortly after that, I got a phone call from (producer) Todd Lieberman. I really didn’t think the movie was going to happen, but when I knew it was, it was great. We had a cool team going: David Gordon Green, (writer) John Pollona, and then Jake. Really? Jake?

On playing a real person:Jake: I’ve done it before, in “October Sky,” “Jarhead,” and “Zodiac.” I wasn’t nervous on this one because John had written such a great script that made me laugh and cry at the same time. But I felt a huge responsibility when I took on the role. I don’t think I considered that tidal wave (of responsibility) coming at me. I thought about how moved I was by the script and the story, and how much I believed in the story.

On initially making contact, then finally meeting each other:Jake: I texted Jeff before we actually met, then we met, then we talked and texted more.

Jeff: You were really busy, but you would come up all the time from New York and say, “Hey, I’m in town, do you want to do something?” That’s how we got to know each other.

Jake: I kept coming up during pre-production, for three or four days. It was back and forth from New York to Boston. I was racking up the miles on my truck.

On why Gyllenhaal was chosen to play Bauman:Jake: It was the decision of a number of people. I think that Todd always believed that I should play the part, and I think David agreed. The part really registered with me. I think I’m really drawn, as a lot of actors are, to characters in crisis, and characters that have a lot of depth. I’m someone who believes in the beauty of dark places, because I believe also in great joy. I don’t think you can have one without the other.

On whether or not Gyllenhaal, in many silent moments and close-ups of his eyes, caught the inner torment that Bauman felt when the events were happening:Jeff: Yeah, that’s the biggest thing and that’s what gets me. I’ve said before that I felt like he stole my soul. That’s really creepy! (laughs) I saw that the first time I saw the trailer.

On how doing this film changed Gyllenhaal’s outlook on life:Jake: I think that I walked in being really intimidated by the story and knowing the intimidation that would be put on me playing him, that Jeff might feel my own fraudulence. But what I was greeted with was a huge open heart, somebody who trusted me in a way that had so much respect for what I do, that he answered my questions and connected with me, and gave me everything he could because he knew somewhere in him that I would do everything I could to do it right. I knew that I could never touch the experience that he had, because I don’t think anybody could really, truly get there. But I think about Jeff every day, in everything I do. I’m constantly reminded to shut my mouth, to think, “That’s not hard, that didn’t hurt.”

Jeff: Like when you stub your toe. (laughs)

Jake: Yeah, when I stub my toe (laughs). You know, I often find myself walking at a pace where I don’t really notice the things around me. But Jeff and I walk a lot of places now when we do stuff together, and just by the nature of the Geniums and the fact that he walks slower, when I’m walking next to him, I walk a little slower, I notice more, I smell more. And that’s the best lesson I’ve learned. So, he’s become a constant reminder to me to walk slower and look around and appreciate where I am.

“Stronger” opens on Sept. 22.

— Ed Symkus writes about movies for More Content Now. He can be reached at esymkus@rcn.com.